Warning w9020: GDAL Error <4> DSM Preview.tif:No such file or directory

Has anyone seen this error message before? This project has been issue after issue and was told by Pix Support to start from scratch (purchased a new computer mid project and thought I could simply move the sub projects/merged projects onto the new unit - not the case - thumbnail errors…‘no such file or directory’ errors etc.). I was able to generate an ortho, .LAS files etc. but when exporting the ortho it would only generate corrupted files (the temporary merged transparent ortho file was ~70GB and the final merge was 2.8GB)…So I was forced to start from pretty well scratch. However I am getting this error - which I have seen before - when merging multiple sub projects together.

The last thing I want to do is process this through stage 2 and have this happen to me again… any thoughts?

[Warning]: Warning w9020: GDAL Error <4> C:/Users/User/Desktop/OLRT NORTH/Trillium North/1_initial/report/html/dsm_preview.tif: No such file or directory

I have read multiple posts where the OP is told that the GDAL error won’t impact outputs… I am hoping this is the case. Any thoughts? I am waiting for the merged quality report to generate and will post it ASAP. Frankly I am sure Pix support is sick of me at this point as this project has had problem after problem.



So basically you should not be worried about warnings until the warring is followed up by an error. The GDAL messages should not affect the processing. However, sometimes in the log file, this warning appears just before an error. That’s why it is hard for me to predict the future as I didn’t see your recent processing files.

I took over your personal ticket from the previous agent as he’s currently out of office due to public holiday. I’m going to follow up with you tomorrow (European swiss time) as soon as I review your files. Hopeful we can find a solution.

Could you tell me why it is crucial for you to merge all the titles? Usually, we don’t recommend for very big, merged projects because of optimisation purposes, even in third-party software.


Hi Beata,

The client came back and asked us to incorporate more control for one area based off a laser scan they did of the pump house in the building. I have had to go back and incorporate these points into Step 1 and am attempting to reoptimize the project. One problem I am having is duplicate images - one data set for a section of the project was incorporated into 2 subprojects that were used to merge. I disabled the images in 1 of the sub project but left them enabled in the other. Upon merging the tie points are visible however (i am assuming) that because they were disabled in one project they are no coming up as disabled in the final merge. This has proven to be quite the issue at this point and have since gone back to enable the areas that I need covered (about 10-15 images). It is the same workflow that I did for the previous point cloud/.LAS generation and only found the issue when i added the tie points to the original merged project however upon reoptimizing with the new control for the small building - with all of the images showing disabled - it completely eliminated the tie points for that section. I have gone back and have enabled the images that i need to be able to identify the control and am attempting to merge again. I should have this done in the next few hours and am hoping that the surface will be present in the final merge. Will this impact the ortho generation when I get to that stage? When i ran stage 2 originally (prior to needing to incorporate the control for this area) it seemed to run through smoothly and generate the ortho… I just don’t have the time to go back and complete this work again.

Thanks for the help


I’m going to follow up with you in the personal ticket.


Hello, I too am receiving this error. Also with dsm_preview.tif.

[Warning]: Warning w9020: GDAL Error <4> D:/Project/1_initial/report/html/dsm_preview.tif: No such file or directory

Every time- 6 count retries! - the ~10K image 1. Initial Processing step stops at 97% on number 5/7.

I know a GPU isn’t configured for this computer, but should this impact the processing?

Hi @Scott_Close,

Please upload your .log file to our OneDrive. I’ll review the file and give you some hints. However, keep in mind that Pix4Dmapper is not optimized to process such a big dataset. You’d have to switch to Pix4Dmatic instead.


Log uploaded @Beata “TipTop.log”

Thank you for your help, I’ve been struggling with this for a week and need to complete the product for a ‘getting impatient client’.

Unfortunately I’ve already purchased a lifetime copy of pix4dmapper- pix4dmatic was not available a couple years ago- so the subscription model pix4d offers would mean I’d have to present more $$ for a more workable option. Can the pix4d team offer those of us who have been struggling with the limits of pix4d mapper an upgrade?

Hi Scott,

Thank you for your fast reply. Speaking about Pix4Dmatic - you can always take an advantage of a trial version and test this product. For personalised offers please contact our Sales Department.

Coming back to the project. It looks like the processing stops at the Quality Report generation. Could you please rerun Step 1 with the Generate Orthomosaic Preview disabled?


@Beata, this was with the Generate Orthomosaic Preview disabled. Only the first attempt had it enabled, the following five count attempts had that selection disabled. I know it seems crazy that the log still reports a [warning] failure at this step.

I also could not complete the install of pix4dmatic due to requirements of needing OpenGL 2.0. Unfortunately, the machine I’m using has no GPU’s as it is a beefy headless host (32 cpu’s, 150gb ram). Maybe this information helps determine the cause of the dsm_preview error.

FWIW, and for the benefit of any other readers, I’ve started a second project also of ~10K images and running everything brand-new (with preview disabled as well). I will report back.

Hi @Scott_Close,

How is it going?

The only case when the GPU can affect your processing is when you have an NVIDIA Cuda device, compatible with OpenGL 3.2 or above that is detected and used for processing and something gets wrong, for instance, the GPU driver is outdated. Therefore, in your example, it shouldn’t matter.

Could you tell me which Pix4Dmapper version are you using? I can’t find the info in the .log file.


Hello @Beata, we got it to work. Having the ‘generate orthomosaic’ checked or not does not impact the following odd results:

  • Even with the error ‘Pix4D encountered an error and had to close’, and that Step 1 never goes ‘green’, Pix4D allows us to proceed onward to Step 2. Meaning, we can continue with the process, even though Pix4D ‘encountered an error and had to close’, and Step 1 never registers as complete.
  • We also get errors at the end of Step 2, if we get the error at the end of Step 1. Error on Step 1 end = error on Step 2 end.
  • When we get the errors at the end of Steps 1 or 2, we can still proceed with the next step, regardless of Pix4D not registering the previous Step as ‘complete’ / going green.

Note, this happens on different versions with different projects, and the errors seem to occur when we have projects greater than ~ 9000 images (basically, every one of our projects).

Just learning that we can continue the Steps regardless of them showing as ‘complete’ (green) has saved us heaps of stress. Hopefully anyone else in this situation discovers this and learns they can proceed.

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Hi Scott,

It’s the first time I hear about such an issue. But, I’m happy that you manage to process your projects anyway. I can only add that Pix4Dmapper is not optimized for such big datasets. Therefore, some error might appear. Our apologies for the trouble.


Hello, I am experiencing the same issue after I classified points as disabled. Below is a copy of my log output.
Processing: Substep Ortho dsm merge started.

Processing: Merge DSM tiles

[Warning]: Warning w9020: GDAL Error <4> C:/Users/tclar/OneDrive/Documents/pix4d/Jera 2021 November/3_dsm_ortho/1_dsm/Jera 2021 November_dsm.tif_tmp.tif: file used by other process

[Error]: Merge tiles: failed to write tile!

[Error]: Merge DSM tiles failed!

[Error]: >>>Merge DSM tiles<<< failed with error (failed to run a step!)!

[Error]: >>>Merge DSM tiles<<< failed with error (failed to run a step!)!

Processing: Substep Ortho dsm merge finished.

Processing: Substep Ortho dsm finished.

I am running windows 11. I processed the whole project with no errors then went to the point cloud and removed points then re-processed step 3. Now I am getting the errors above.

Hi tclark,
I would suggest making sure your GPU driver is up to date. I would also suggest looking at our community page regarding Windows 11.